11/27: Urinary System

Question 1

The kidney has several important homeostatic, hormonal, and metabolic
functions that include:

Answer 1

• The maintenance of water and electrolyte homeostasis.
• Regulation of acid-base balance in conjunction with the respiratory system.
• Excretion of metabolic waste products, especially the toxic nitrogenous
  compounds.
• Production of renin for blood pressure control and erythropoietin, which
  stimulates red blood cell production in the bone marrow.
• Conversion of vitamin D into active form for the regulation of calcium
  balance

Question 2

How many segmental (lobar) aa are per kidney?

Answer 2

5

Question 3

Each lobar artery is an?

Answer 3

“end artery”

Question 4

What does each segemental artery give off?

Answer 4

Interlobar aa
arcuate aa
intralobular aa
afferent arterioles

Question 5

What drains the glomeruli and forms capillary networks?

Answer 5

Efferent arterioles

Question 6

What drains cortical nephrons and forms peritubular capillary network while taking up substances resorbed by tubular epithelium?

Answer 6

Efferent arterioles

Question 7

What is the functional unit of the kidney?

Answer 7

Nephron

Question 8

What are the two main components of the kidney?

Answer 8

Renal corpuscle and renal tubule

Question 9

What filters blood plasma?

Answer 9

renal corpuscle

Question 10

What modified filtrate to form urine?

Answer 10

Renal tubule

Question 11

What is the nephron composed of?

Answer 11

Renal corpuscle
Proximal convoluted tubule
Loop of henle
Distal convoluted tubule
Collecting tubule/duct

Question 12

Where are capillaries found around?

Answer 12

Proximal/Distal convoluted tubule and loop of henle

Question 13

What capillaries are found around PCT/DCT? LH?

Answer 13

Pertibular capilaries; Vasa Recta

Question 14

What capillaries are found around LH?

Answer 14

Vasa recta

Question 15

What filters fluid from blood?

Answer 15

Renal corpuscle

Question 16

What portion modifies filtrate into urine?

Answer 16

Tubular portion

Question 17

The type of nephron depends on?

Answer 17

Location in cortex and of their henle loop

Question 18

What types of cortical can there be?

Answer 18

Subcapsular (short loops)
Midcortical (inetermediate)
Juxtamedullary (long)

Question 19

What is the role of the kidneys?

Answer 19

Maintenance of internal fluid composition and volume (internal environment)

Question 20

Capillaries invaginate into?

Answer 20

Bowman’s capsule

Question 21

What are the capillaries in contact with?

Answer 21

Visceral layer (podocytes)

Question 22

What epithelium is the parietal layer?

Answer 22

Simple squamous epithelium

Question 23

What is the renal corpuscle separated by?

Answer 23

Urinary (bowman’s) space

Question 24

What is the function of mesengial cells?

Answer 24

Secrete mesangial matrix, vasoactive factors, and cytokines

Question 25

What are the main structural compinents of the mesangial matrix?

Answer 25

Collage type IV Laminin Fibronectin Proteoglycans

Question 26

What is the primary phagocytic function of mesangial cells?

Answer 26

Remove trapped residues and aggregated protein from the basement membrane, thus keeping the filter free of debris

Question 27

What has been suggested in changing the filtration pressure of the glomerulus?

Answer 27

Contractile properties of mesangial cells

Question 28

Where are extraglomerular mesangial cells located?

Answer 28

Between the afferent arteriole and the efferent arteriole towards the vascular pole

Question 29

Where are intraglomerular mesangial cells located?

Answer 29

Inside the glomerulus in between the capillaries

Question 30

Fluid from capillaries leaks into the urinary space through?

Answer 30

Complex filtration barrier

Question 31

What are the 3 components of the filtration barrier?

Answer 31

1. Fenestrated capillary endothelium 2. Basal lamina (basement membrane) 3. Podocytes of the visceral layer of bowman's capsule (epithelial cells (podocytes) with pedicles (foot projections))

Question 32

What is on some components of both basal lamina (glycoprotein podocalyxin) and surface of podocyte processes?

Answer 32

High polyanionic charge

Question 33

What type of capillaries are glomerular capillaries?

Answer 33

Fenestrated Large pores not covered by a diaphragm

Question 34

What are glomerular capillaries permeable to?

Answer 34

Water, urea, glucose, and small proteins

Question 35

What is the barrier on glomerular capillaries for?

Answer 35

Formed elements in blood and large macromolecules

Question 36

What does the lamina rarae contain?

Answer 36

Type IV collagen Laminin Fibronectin Negatively-charged proteoglycans

Question 37

What crosses the basal lamina freely?

Answer 37

Water, ions, and small organic molecules

Question 38

What crosses the basal lamina reasonably freely?

Answer 38

Peptide hormones and small proteins

Question 39

What does each pedicel have?

Answer 39

Glycocalyx of negatively-charged podocalyxin

Question 40

What are pedicels separated by?

Answer 40

Cleft filtration slits

Question 41

What are pedicles covered by?

Answer 41

Porous slit diaphragm made of protein nephrin

Question 42

What does the pedicel additionally act as?

Answer 42

Barrier to large macromolecules, proteins, negatively charged molecules and blood cells

Question 43

What have phagocytic functions?

Answer 43

Podocytes

Question 44

Where does blood enter glomerulus via?

Answer 44

Afferent arterioles

Question 45

What forces fluid through fenestrae of capillary endothelium?

Answer 45

Arteriole pressure

Question 46

What is trapped by the basal lamina?

Answer 46

Large molecules

Question 47

What are stopped by the basal lamina and podocytes?

Answer 47

Negatively charged molecules

Question 48

What passes through pores in slit diaphragm to enter the urinary space -> PLT?

Answer 48

Fluid

Question 49

What is the site of "bulk operations"?

Answer 49

Proximal convoluted tubule

Question 50

Where does the site of bulk operations begin?

Answer 50

At urinary pole

Question 51

What is the proximal convoluted tubule the primary site for?

Answer 51

Water resorption, removes 75% of water and ions (Na, Cl)

Question 52

What is found only in the cortex?

Answer 52

Proximal convoluted tubule

Question 53

What is the proximal convoluted tubule lined by?

Answer 53

Eosinophilic cuboidal/low columnar epitheliam

Question 54

What is in the center of the proximal convoluted tubule?

Answer 54

Centrally placed nucleus

Question 55

What is the border of a proximal convoluted tubule?

Answer 55

Microvilli and well-defined brush border

Question 56

Describe the lateral border of the proximal convoluted tubule

Answer 56

Indistinct due to interdigitations

Question 57

The proximal tubule has extensive reabsorption of...

Answer 57

glomerular filtrate (microvilli)

Question 58

The proximal tubule has a reduction in...

Answer 58

fluid volume

Question 59

What is endocytosed in the PCT?

Answer 59

Proteins and small peptides

Question 60

What 3 things pass through the proximal tubule via a small transmembrane channel?

Answer 60

Na+ (active transport) Cl- (passive diffusion) H2O (AQP-1, aquaporin-1)